The present invention relates to a stacked coil assembly for a stator, and more particularly, to a stator of an electric rotary machine.
Conventionally, in a stator of an electric rotary machine, a concentrated winding system is utilized in which a coil is wound around a tooth portion of the stator by utilizing a bobbin. As shown in FIG. 21, a stator is comprised of a tooth portion 210 and a bobbin portion 212. A coil (not shown) is wound tightly on a bobbin 212. Next, the bobbin 212 with the winded coil is mounted on the tooth portion 210. Next, the tooth portion 210 having the bobbin 212 mounted thereon is combined together with a stator core to form the stator.
However, in the conventional method, coil is wound around the bobbin 212 very tightly causing excessively large winding tension. Thus, the bobbin 212 is frequently damaged and, in turn, the tooth portion 210 coupled to the bobbin 212 can be damaged as well. This results in an ineffective performance of the stator. Also, if the bobbin 212 is made thicker to protect it from breakage or damage, then the heat conducting property of the bobbin 212 is deteriorated, damaging the coil, due to the excessively high temperatures since cooling of the coil is hindered.
The present invention provides a stacked coil assembly for a stator of an electric rotary machine in which the performance of the stator is improved and the above discussed problems of the conventional art is avoided.
In an object of the present invention a coil assembly is provided comprising at least two end coil pieces having a U-shaped end and an open end, the open end comprising a first end and a second end, the second end having a terminal length greater than the first end. Further, at least one middle coil piece is provided stacked between the end coil pieces having a U-shaped end and an open end, the open end comprising third ends having a terminal length equal to the first end. Also, at least two intermediate coil pieces are provided, each being separately stacked between the end coil piece and the middle coil piece having a U-shaped end and an open end, the open end comprising fourth ends having a terminal length shorter than the first and third ends with the first and third ends being connected to an adjacent fourth end.
In another object of the present invention a coil assembly is provided comprising at least two end coil pieces having a U-shaped end and an open end, the open end comprising a first end and a second end, the second end having a terminal length greater than the first end. Further the invention provides at least one middle coil piece stacked between the end coil pieces having a U-shaped end and an open end, the open end comprising third ends having a terminal length equal to the first end. Also, at least two intermediate coil pieces are provided each being separately stacked between the end coil pieces and the middle coil piece having a U-shaped end and an open end, the open end comprising fourth ends having a terminal length shorter than the first and third ends wherein the ends of each of the respective coil pieces lie on a different plane with respect to each other and the first and third ends being connected to an adjacent the fourth end lying on the same plane.
In yet another object of the present invention a stator is provided comprising a core having an entry side and an exit side, a tooth portion having two contact sides provided in an inner periphery of the core, a slot provided in each of the contact sides and a coil assembly provided in the slot. The coil assembly further comprising at least two end coil pieces having a U-shaped end and an open end, the open end comprising a first end and a second end, the second end having a terminal length greater than the first end. Further, the invention provides at least one middle coil piece stacked between the end coil pieces having a U-shaped end and an open end, the open end comprising third ends having a terminal length equal to the first end and at least two intermediate coil pieces, each being separately stacked between the end coil piece and the middle coil piece having a U-shaped end and an open end, the open end comprising fourth ends having a terminal length shorter than the first and third ends with the first and third ends being connected to an adjacent fourth end.
In another object of the present invention a stator is provided comprising a core having an entry side and an exit side, a tooth portion having two contact sides provided in an inner periphery of the core, a slot provided in each of the contact sides and a coil assembly provided in the slot. The coil assembly further comprises at least two end coil pieces having a U-shaped end and an open end, the open end comprising a first end and a second end, the second end having a terminal length greater than the first end. Further, at least one middle coil piece is provided that is stacked between the end coil pieces having a U-shaped end and an open end, the open end comprising third ends having a terminal length equal to the first end. Further, at least two intermediate coil pieces are provided, each being separately stacked between the end coil piece and the middle coil piece is provided having a U-shaped end and an open end, the open end comprising fourth ends having a terminal length shorter than the first and third ends and wherein the ends of each of the respective coil pieces lie on a different plane with respect to each other and the first and third ends being connected to an adjacent the fourth end lying on the same the plane.
In another object of the present invention a method of fabricating a coil assembly is provided comprising the steps of providing at least two end coil pieces having a U-shaped end and an open end, the open end comprising a first end and a second end, the second end having a terminal length greater than the first end. The method further provides the step of providing at least one middle coil piece stacked between the end coil pieces having a U-shaped end and an open end, the open end comprising third ends having a terminal length equal to the first end. Further, the method provides the step of providing at least two intermediate coil pieces, each being separately stacked between the end coil piece and the middle coil piece having a U-shaped end and an open end, the open end comprising fourth ends having a terminal length shorter than the first and third ends and connecting the first and third ends to an adjacent fourth end.
In another object of the present invention a method of fabricating a coil assembly is provided comprising the steps of providing at least two end coil pieces having a U-shaped end and an open end, the open end comprising a first end and a second end, the second end having a terminal length greater than the first end. Further, the method provides the step of providing at least one middle coil piece stacked on the end coil piece having a U-shaped end and an open end, the open end comprising third ends having a terminal length equal to the first end. Further, the method provides the step of providing at least two intermediate coil pieces each being separately stacked between the end coil piece and the middle coil piece having a U-shaped end and an open end, the open end comprising fourth ends having a terminal length shorter than the first and third ends. The method further provides the step of connecting the first and third ends to an adjacent the fourth ends lying on the same the plane wherein the ends of each of the respective the coil pieces lie on a different plane with respect to each other.
In another object of the present invention a method of fabricating a stator is provided comprising the steps of providing a core having an entry side and an exit side, providing a tooth portion having two contact sides in an inner periphery of the core, providing a slot in each of the contact sides and providing a coil assembly in the slot. The step of providing a coil assembly further comprising the step of providing at least two end coil pieces having a U-shaped end and an open end, the open end comprising a first end and a second end, the second end having a terminal length greater than the first end. Further, the method provides providing at least one middle coil piece stacked between the end coil pieces having a U-shaped end and an open end, the open end comprising third ends having a terminal length equal to the first end. Further, the method provides the step of providing at least two intermediate coil pieces stacked between the end coil piece and the middle coil piece having a U-shaped end and an open end, the open end comprising fourth ends having a terminal length shorter than the first and third ends and connecting the first and third ends to an adjacent fourth end.
In yet another object of the present invention, a method of fabricating a stator is provided comprising the steps of providing a core having an entry side and an exit side, providing a tooth portion having two contact sides in an inner periphery of the core, providing a slot in each of the contact sides and providing a coil assembly in the slot. The step of providing a coil assembly further comprising the step of providing at least two end coil pieces having a U-shaped end and an open end, the open end comprising a first end and a second end, the second end having a terminal length greater than the first end. Further, the method provides the step of providing at least one middle coil piece stacked between the end coil pieces having a U-shaped end and an open end, the open end comprising third ends having a terminal length equal to the first end. The method further provides at least two intermediate coil pieces, each being separately stacked between the end coil piece and the middle coil piece having a U-shaped end and an open end, the open end comprising fourth ends having a terminal length shorter than the first and third ends. The method further provides the step of connecting the first and third ends to an adjacent fourth end lying on the same the plane wherein the ends of each of the respective the coil pieces lie on a different plane with respect to each other.